In the field of ordinary structural concretes, in particular concretes of the C25/30 type (that is for which the typical compressive strength 28 days after mixing, measured on a 16×32 cm cylinder is at least 25 MPa, according to the EN 206-1 standard), it is noted that the quantity of cement is typically from 260 to 360 kg per m3 of concrete. Current European standards moreover do not provide for levels of cement less than 260 kg/m3 for ordinary structural concretes.
Now, the processes for cement production, and more particularly its essential constituent, clinker, are responsible for high emissions of carbon dioxide. The production of grains of clinker in fact requires:                a) pre-heating and decarbonation of the raw meal, which is obtained by grinding the raw materials, which are, in particular, limestone and clay; and        b) firing or clinkering the meal at a temperature of 1450-1550° C., followed by rapid cooling.        
These two stages produce CO2, on the one hand as a direct product of the decarbonation and on the other hand as a by-product of the combustion which is implemented in the firing stage in order to raise the temperature.
The emission level reaches approximately 560 kg of CO2 per tonne of binder for a binder typically used to produce a C25/30 concrete, which contains 65% of clinker (on the basis of an average of 850 kg of CO2 emitted per tonne of clinker), and this is even greater for an ultra-high performance concrete.
Now, the high emissions of carbon dioxide in standard processes for the production of cement and concrete compositions constitute a major environmental problem, and in the current context, are subject to high economic penalties.
A strong need therefore exists for a process capable of producing concrete with reduced associated emissions of carbon dioxide, the said concrete providing satisfactory mechanical properties, and in particular equivalent to those of existing currently, in view of its use in the construction industry. In particular, the desired typical compressive strength of the concrete should be greater than or equal to 25 MPa after 28 days, in conformity with the EN 206-1 Standard. On the other hand, the desired average compressive strength of the concrete should be greater than or equal to 4 MPa, preferably greater than or equal to 5 MPa, at 20° C. 16 hours after mixing, the measurement being done according to the EN 12390-3 Standard on cylindrical specimens, kept according to the EN 12390-2 Standard at 20° C.±2° C. and relative humidity greater than 95%. The desired wet concrete's rheological properties should also be satisfactory, that is in particular that the viscosity of the mixed mixture be low enough to allow easy handling, even 2 hours after mixing.